There are many health related benefits believed to be associated with metals and metal ions. For example, zinc is known to be used in the treatment of acne, dandruff, and diaper rash; as well as a natural sunscreen. Silver is known for its antimicrobial properties. Copper has been used in medicine for many years for skin repair and regeneration. Copper increases oxygen transport, neutralizes free radicals, and inhibits growth of mold and mildew. For these reasons and others, there is a desire to incorporate metals into fabrics, finished garments, and other products.
In the field of applying metals to fabrics there are two main methods of doing so: extrusion and electroplating. Extrusion requires the metals be encapsulated within the fiber of the fabric. Typically, the metal is added to a slurry with the polymer of the fabric and an impregnated fiber is extruded (see, e.g., U.S. Pat. No. 8,741,197). This method limits the addition of the metal to the extruded fiber itself, and does not allow for treatment of woven or nonwoven textiles in their finished form. Further, fibers made from this method are sensitive to certain chemicals. For example, garments made from such products are degraded when exposed to fabric softeners.
It is further known that textiles may be plated with metals. Electroplating is known way to apply metals to fabrics. This process requires a conductive material on which to deposit metals. Electroless plating does not require an electric current, but is a more expensive option and is limited to autocatalytic reduction reactions, limiting the types of metals available for use.
It is desired to provide a method for applying metals in a reactive form, ions, complexes or salt forms, to the surface of a substrate.
It is desired to provide a method of applying reactive metals to the surface of articles such as textiles, foams, vulcanized or molded products, including fibers, woven and non-woven fabrics, and finished products such as garments and accessories without the use of electric current or excess chemicals.
It is further desired to provide a method of applying reactive metals to the substrate wherein the substrate retains its physical properties.
The present invention employs polymers containing reactive metals to achieve these objectives. Use of metal ions to cross-link polymer chains and encapsulating metal ions within a polymer has been taught in the art. Cross-linked polymers derived from acrylate, acrylate derivatives and the like are also well covered in the prior art.
For instance, U.S. Pat. No. 4,484,926 to Atlas discloses fibers made from cross-linked hygroscopic homopolymers with high moisture regain and antistatic properties. Suitable monomers for the homopolymers include acrylic acid and methyl acrylate. Atlas does not disclose copolymers.
U.S. Pat. No. 4,968,734 to Gaidis et al. discloses a copolymer compound composed of acrylic or methacrylic acid and hydroxyl alkyl ester of acrylic or methacrylic acid for use in concrete compositions to address flow and setting issues.
U.S. Pat. No. 5,071,681 to Manning et al. discloses a non-woven fabric having a web of cellulose fibers treated with a hydrophilic, absorbent polymer compound for enhancing water absorption capacity. The absorbent polymers can be homopolymers of acrylic or methacrylic acid or carboxylated polymers derived from acrylamide. The absorbent polymers may also be copolymers of acrylic or methacrylic acid, with one or more ethylenically unsaturated comonomers. The polymers are cross-linked after application to the fabric web using organic cross-linking agents such as polyglycidyl ether, di- and polyfunctional epoxide, or by complexing with metal ions having a valence greater than one and coordination greater than two (e.g., zinc, iron, and tin).
U.S. Pat. No. 5,505,999 to Krishnan et al. discloses a textile substrate coated with a polymer composed of unsaturated mono- or dicarboxylic ester monomer (e.g., methyl methacrylate) and an aliphatic conjugated diene monomer. The polymer may also contain an unsaturated mono- or dicarboxylic acid monomer (e.g., acrylic acid). The polymer can further include crosslinking agents and other additives to improve physical and mechanical properties.
U.S. Pat. No. 5,599,898 to Hartmann et al. discloses slightly swellable amino containing “popcorn” polymers which are suitable for removing metal ions (e.g., Cu2+ and Zn2+) from solutions. The polymers are made from monomers of vinylcarboxamides, monoethylenically unsaturated monomers (e.g., methyl acrylate, acrylic acid), and a compound with at least two ethylenically unsaturated double bonds as a crosslinking agent (e.g., ethylene glycol diacrylate, ethylene glycol dimethacrylate). There is no teaching of use or application of such “popcorn” polymers with textiles or fabrics.
U.S. Pat. No. 7,074,750 to Hamers et al. discloses cationically modified nanoparticles for the soil release treatment of textile surfaces. The nanoparticles are made of hydrophilic cross-linked polymers comprised of at least 60% carboxyl-containing ethylenically unsaturated monomers (e.g., acrylic acid and methacrylic acid), and a combination of water-insoluble monoethylenically unsaturated monomer (e.g., methyl acrylate), polyethylenically unsaturated monomer, sulfonic or phosphonic acid containing monomer, and/or water-soluble nonionic monomer. The nanoparticles are coated with cationic polymers, polyvalent metal ions or cationic surfactants. The cationic polyvalent metal ions disclosed include zinc and copper, although copper is noted as not being desired in all applications.
U.S. Pat. No. 8,506,788 to Wang et al. discloses leveler compounds for copper plating that are used manufacture semiconductors, circuit boards, etc. The leveler compounds have metal ions, electrolyte, and polymeric leveling agents made up of the following monomers: ethylenically unsaturated cross-linking agent, ethyleneically unsaturated nitrogen containing heterocyclic monomer and methacrylate monomer. The metal ions are preferably copper ions.
In spite of these efforts, all of the presently existing textile fibers used containing and releasing metal ions still suffer from several shortcomings. For instance, these fabrics are limited in color and may be clingy and staticy, depending on the textile used. Research in this area has shown that these shortcomings originate, at least in part, from the opacity of the metal coating solution.
Copper(II) oxide or cupric oxide (CuO) is the higher oxide of copper. It is a black solid with an ionic structure and can be an irritant. However, the risk of dermal sensitivity is considered extremely minimal. In comparison, Copper (I) oxide or cuprous oxide (Cu2O) is typically a red-colored solid, though it can appear either yellow or red, depending on the size of the particles. When combined, the two ions result in copper-colored solutions. It is difficult to impart fabrics with various colors if including these species of copper because the reddish-copper color predominates.
Accordingly, it is desired to improve the opacity and color of metal containing solutions for imparting onto fabrics.
It is, therefore, an object of the present invention to provide metal-infused, light weight fabrics which may be woven, non-woven, or knitted and which can be used to prepare articles of apparel and home goods, which can be produced in a wide range of colors, are comfortable and can release ions on a time delay, all while being environmentally conscious and safe for human wear.
A further object of the invention is to provide a metal-containing polymer for coating or infusion with substrates of various types, in particular various types of fabric. It is an object of the invention that such polymer have sufficient water solubility and chemical reactivity, such that metal ions are released when the substrates come in contact with moisture.
It is another object of the invention that various colors of substrate are able to be manufactured containing a metal-infused polymer.
A still further object of the invention is to manufacture metal-containing fabrics that are inexpensive to manufacture and can be made using standard equipment in an environmentally conscious and safe manner.
It is the object of the present invention to provide a method for applying or delivering a reactive metal to the surface of a substrate by a carrier or vehicle. The present invention aims to improve upon the deficiencies of prior methods and techniques for incorporating reactive metals into fabrics, textiles, and other products.
Particularly, it is an object of the present invention to provide effective application of reactive metals, such as metal ions and reactive metal salts, to products especially in their finished form.
It is an object of the current invention that the metal ions and metal salts bound to the substrate are mobile so that they can be transported outside of the fabric or substrate.
It is a further object of the present invention to provide the time release of metal ions from the substrate to an external object.